Patient interface systems

ABSTRACT

A patient interface system includes a nasal seal of flexible material to communicate with at least one airway of the patient, and a primary headgear from which the nasal seal is suspended, said primary headgear having at least one aperture though which at least a portion of the nasal seal is inserted with the primary headgear wrapping about at least one portion of the nasal seal in a sling-like fashion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 16/015,388, filed Jun. 22, 2018, now allowed, which is a continuation of U.S. application Ser. No. 14/534,251, filed Nov. 6, 2014, now U.S. Pat. No. 10,029,063, which is a continuation of U.S. application Ser. No. 13/372,792 filed Feb. 14, 2012, now U.S. Pat. No. 8,905,031, which is a continuation-in-part of U.S. application Ser. No. 12/478,537 filed Jun. 4, 2009, now U.S. Pat. No. 8,291,906, which claims the benefit of U.S. Provisional Application Nos. 61/058,659 filed Jun. 4, 2008 and 61/080,847 filed Jul. 15, 2008, and this application also claims benefit of U.S. Provisional Application Nos. 61/457,272, filed Feb. 16, 2011 and 61/552,064 filed Oct. 27, 2011, each of which is incorporated by reference in its entirety.

FIELD OF THE TECHNOLOGY

The present technology relates to patient interface systems for delivery of a flow of breathable gas to a patient. The present technology also relates to patient interface systems that may include adhesive(s) to support the patient interface in engagement with the patient and/or a patient interface positioning and/or support structure.

BACKGROUND OF THE INVENTION

The use of positive airway pressure (PAP) for the treatment of sleep disordered breathing (SDB), such as obstructive sleep apnea (OSA), was disclosed in U.S. Pat. No. 4,944,310. Treatment using PAP, which may be continuous PAP (CPAP), involves the use of a patient interface which is attached to the patient's face for the provision of the flow of breathable gas. PAP treatment involving the use of a patient interface that is sealingly attached to the wearer's face may be referred to as closed PAP.

For patients that require treatment of OSA, a patient interface, e.g. a mask, that forms a seal with the patient's airways may be required. However, the patient may find adapting to current interfaces difficult. For example, the patient may have difficulty sleeping in a familiar, comfortable position once the mask, including the headgear and air delivery hose, are fitted to the patient to provide the required seal. Although the mask is capable of providing a seal and the prescribed pressure, the patient may be reluctant to use the mask due to the problem of sleeping comfortably while wearing the mask. The patient may also find the mask assembly too obtrusive. These factors may result in the patient abandoning the treatment.

SUMMARY OF THE TECHNOLOGY

One example of the present technology relates to the use of a silicone nasal or nares seal assembly and a relatively small headgear that may work in conjunction with an adhesive pad. The small headgear may be positioned, for example, between the nasal or nares seal and a gusset or connecting region of the nasal or nares seal assembly. The headgear may be attachable to the adhesive pad, e.g., by an attachment mechanism such as hook and loop material. The nasal or nares seal may be in the form of nasal prongs or nozzles, or it may be a nasal or nares seal that seals around both nares in the small region between or in the vicinity of the upper lip and the tip of the user's nose.

Another example of the present technology relates to a patient interface system comprising a nasal seal of flexible material to communicate with at least one airway of the patient; and a primary headgear from which the nasal seal is suspended, said primary headgear including a fabric and/or textile material having at least one aperture though which at least a portion of the nasal seal is inserted with the primary headgear wrapping about at least one portion of the nasal seal in a sling-like fashion. The headgear may work in conjunction with a securing pad that is secured to the patient's face, e.g., an adhesive pad that is adhesively secured to the nasal bridge region of the patient's face.

Another example of the present technology relates to a patient interface system comprising a nasal seal of flexible material to communicate with at least one airway of the patient, and a primary headgear to which the nasal seal is attached, said primary headgear including a fabric and/or textile material connected to at least a portion of the nasal seal, with the primary headgear removably attachable to an adhesive strip positioned on the patient.

Another example of the present technology relates to a patient interface system comprising a nasal seal of flexible material to communicate with at least one airway of the patient; and a primary headgear in which the nasal seal and primary headgear are positively located, inter-engaged, interlocked, intermeshed, sandwiched, and/or abutted against, etc., one another. For example, a portion of the nasal seal may extend through an aperture or slot, etc., in the primary headgear, and/or vice versa.

Another example of the present technology relates to a patient interface including an unobtrusive or low profile nasal seal (e.g., nozzles or a nares seal) that may be securely suspended from a relatively small headgear. The headgear and nasal seal are structured to inter-engage, etc. with one another, without requiring one or more separate clips to connect the headgear to the patient interface.

Another example of the present technology relates to a patient interface that can be suspended on a patient's face without any “hard” parts, such as a polycarbonate frame or “shell” to which many typical cushions are connected, and/or so-called headgear clips which allow connection between headgear straps and the frame/shell. For example, the patient interface may include a soft and complaint nasal seal (e.g., nasal only, oro-nasal, nozzles, prongs, nares seal, etc.), and a headgear made of soft and flexible material, e.g., composite materials such as laminated foam and fabric, a non woven fabric, a mesh, etc. The headgear may be suspended from a securing pad that can be adhesively or otherwise supported on the patient's face (e.g., nasal bridge).

Other aspects, features, and advantages of this technology will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of this technology.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the various sample embodiments, wherein:

FIG. 1 is a perspective view of a patient interface system according to an example of the present technology in an operational position on a model patient's head;

FIG. 2 is a front view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is an exploded view of the patient interface system shown in FIGS. 1-3;

FIG. 5 is a top view of a nasal seal and primary headgear subassembly thereof;

FIG. 6 is an exploded view of the nasal seal and primary headgear subassembly shown in FIG. 5 (with a variant of the primary headgear);

FIG. 7 is a top perspective view of an optional secondary headgear for a patient interface according to an example of the present technology;

FIG. 8 is a side view of a variant of the patent interface system of FIG. 1 and the secondary headgear of FIG. 7 in an operational position on a model patient's head;

FIG. 9 is a side view of a variant of the patent interface system of FIG. 1 and the secondary headgear of FIG. 7 in an operational position on a model patient's head;

FIGS. 10-21 are top views showing a plurality of small primary headgears according to examples of the present technology;

FIG. 22 is a front view of a patient interface system according to an example of the present technology in an operative position on a model patient's head in use;

FIG. 23 is a top perspective view of the nasal seal and primary headgear subassembly shown in FIG. 22;

FIG. 24 is rear perspective view thereof; and

FIG. 25 is top view thereof.

DETAILED DESCRIPTION

The following description is provided in relation to several examples which may share common characteristics and features. It is to be understood that one or more features of any one example may be combinable with one or more features of the other examples. In addition, any single feature or combination of features in any of the examples may constitute an additional feature or features that may be independently claimed and pursued.

In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.

The term “air” will be taken to include breathable gases, for example air with supplemental oxygen. It is also acknowledged that the blowers described herein may be designed to pump fluids other than air.

As used herein, the term “patient interface system” refers to a structure configured to engage the face of a patient and deliver the flow of breathable gas to the patient's airways.

Examples of the present technology relate to the use of an existing or slightly modified silicone nasal or nares seal and a small headgear that may work in conjunction with a securing or adhesive pad. The small headgear may be positioned, for example, between a nasal or nares seal and a gusset, base or connecting region of the nasal or nares seal assembly. The headgear may be attachable to the adhesive pad, e.g., by an attachment mechanism such as hook and loop material, or adhesive. The nasal or nares seal may be in the form of nasal prongs or nozzles, or it may be a nasal or nares seal that seals around both nares in the small region between or in the vicinity of the upper lip and the tip of the user's nose, a shown, for example, in PCT/AU2010/000684 filed Jun. 2, 2010, incorporated by reference in its entirety.

FIGS. 1-3 show a patient interface system 5 according to an example of the present technology. Patient interface system 5 includes a nasal seal 10 of flexible material, e.g., silicone or another elastomer, to communicate with at least one airway of the patient. A primary headgear 15 is provided from which the nasal seal 10 is suspended. The assembly or sub-combination of the nasal seal 10 and the primary headgear 15 may be suspended from the patient's head (e.g., nose), using a securing pad, e.g., an adhesive pad 20.

The patient interface system 5 may include a short tube 25 having a first end 30 to connect with the nasal seal 10, and a second end 31 to connect with an air delivery tube via a swivel 32. The first end 30 of the short tube may include a gusset or decoupling joint 35 (FIG. 4) to accommodate for tube drag and rotational forces. The patient interface system may include a vent 40, e.g., a plurality of holes 45, to allow for CO₂ gas washout.

The primary headgear 15 includes a fabric and/or textile material or layer having at least one aperture 50 (FIG. 6) though which at least a portion 55 of the nasal seal 10 is inserted, with the primary headgear 15 wrapping about at least one portion (e.g., the nozzles) of the nasal seal in a sling-like fashion. The primary headgear 15 includes a center section 60 having the at least one aperture 50 through which the nozzle heads 150 of the nasal seal extend such that the nasal seal is positively located against a rim 65 surrounding the aperture 50. The at least one aperture 50 may include a reinforcement at least partially about the rim, e.g., stitching or a donut/torus shaped reinforcement, to prevent tearing/deformation.

The headgear 15 may be made from a laminate including multiple layers, e.g., a fabric and/or textile or textile and flexible polymeric material such as silicone; a soft, breathable and flexible patient contacting or facing inner layer such as fabric and/or textile, a soft and flexible outer layer and a foam-type layer between the inner and outer layers. The headgear may be reinforced with a stiffening material (e.g., plastic or nylon) to add rigidity in one or more regions. The primary headgear 15 is made of a soft and flexible material, such as that sold under the trade name “Breath-O-Prene”.

In an alternative form, primary headgear 15 may be constructed from or constructed in part from a deformable plastic such as silicone, thermoplastic elastomer, etc. The deformable plastic may be able to change shape e.g. from a flat position to an in use curved position, be comfortable on the user's face, and receive nozzle heads 150. In a further example, the first attachment region 80 may be, for example, hook portions that are integrally molded with primary headgear 15. First attachment region 80 may be formed of the same material as primary headgear 15 or a different material than primary headgear 15. In a further example, primary headgear 15 may include a stiffer material in some portions for reinforcing, e.g. rims 65 may be lined with a substantially stiffer material than other regions of primary headgear 15. Such an arrangement may ensure structure integrity and prevent tearing or wear of the primary headgear in these stiffened regions. It may also aid in aligning and fitting primary headgear 15 to nozzle heads 150, and supporting nozzle heads 150 in position.

The primary headgear includes at least one arm 70 extending from the center section 60. Each arm 70 may extend away from the center section 60 linearly, or in a curved or curled fashion, and/or at an angle β (e.g., about 20°-140° from horizontal) relative to the center section as shown in the variants in FIGS. 10-21. This arrangement may enable arms 70 to be positioned on the flares or sides of the patient's nose in use, rather than positioning on the patient's cheeks or top lip. Alternatively, or in addition, each arm 70 may include a connection 75 provided between the center section 60 and the arm 70 (see for example FIGS. 12 and 15). Connection 75 may be a portion of fabric or other material that forms a bridge between the center section 60 and the arm 70. Connection 75 may include, for example, supplemental attachments for receiving a supplemental headgear. For example, connection 75 may include an eye and a supplemental headgear may include a hook, the eye adapted to receive the hook. Alternative removably attachable mechanisms may be possible, for example hook and loop, buttons, etc.

The primary headgear may include two or more arms 70 extending from the center section 60, e.g., a pair of laterally extending arms as shown in FIGS. 6 and 10-25. Each arm may include a first attachment region 80 provided at or near an end of each arm. Each first attachment region 80 may include a hook or loop type fastener, for attachment to a second attachment region, e.g., loop or a hook type fastener 85, provided on the securing or adhesive pad 20 provided to the patient's face. The securing pad may be supported on the patient's head with one or more straps.

The securing pad 20 may be in the form of an adhesive pad that has a first side 90 provided with an adhesive to adhesively contact the patient's face (e.g., nasal bridge region) and a second side 95 to engage or receive a portion (e.g., the arm(s)) of the primary headgear. The second side 95 may include a second attachment region to engage with the first attachment region 80. The first and second attachment regions may be secured to one another via a hook and loop fastening system. However, the first and second attachment regions may be secured to one another via alternative means, for example adhesive, hook and eye clasp.

Alternatively, each first attachment region 80 may include an adhesive to adhere directly to the patient's face in use, in which case the adhesive pad 20 may not be required. In addition, the first attachment region 80 may be in the form of a clip that is received within a receiving portion of the pad 20.

At least an upper or front portion 100 of a perimeter of the center section 60 is formed to follow the general shape of the apertures 50, so as to form a gap 105 between the apertures. The at least one arm 70 may be angled or oriented towards the front or upper portion 100. In the example of FIG. 6, the at least one arm is curved or curled in towards an upper portion of the center section.

A lower portion 110 of a perimeter is cut out or arc shaped to accommodate the patient's septum or top lip. Preferably, lower portion 110 may avoid or substantially avoid positioning between the mask and the patient's top lip. This arrangement may permit the mask to rest on the patient's top lip, and therefore align with the patient's nares. Alternatively, this arrangement may prevent the mask from tilting towards the patient's nose tip and away from the top lip or shifting the mask in the superior direction of the patient's nose, as the lower portion may contacting the patient's top lip and then the mask thereby offsetting the position of the mask. In general the lower or rear portion may be said to have a generally concave shape, e.g., FIGS. 10-18 and 20-22. Lower portion may have any other shape adapted to avoid the patient's top lip, for example the lower portion may comprise a slit or perforation.

An upper portion of the center section may include a raised flap 115 (FIGS. 1-4 and 17-19) to cover the patient's nares and/or portion of nasal seal in use, and/or to support the nasal seal. Raised flap 115 may be substantially curved or wrapped around the patient's nose tip. This may be achieved by flexing the material around the patient's nose tip. Alternatively, raised flap may comprise a dart and stitched portion, the dart and stitching adapted to provide the raised flap with a three dimensional curvature.

Nozzles

The primary headgear 115 may include a pair of apertures 50 provided in the center section 60, and the nasal seal 10 may be in the form of a pair of generally hollow nozzles 120, prongs or puffs that extend though respective ones of the pair of apertures 50. The nozzles 120, e.g., the widest parts 125 have a cross sectional size that is greater than a cross sectional size of the apertures 50 (in at least one orientation). The apertures 50 may be round or the apertures may be oval and have major axes that converge towards one another at an angle X of about 15°−45°, e.g., 30°, in a direction oriented towards the front side 100 of the primary headgear (FIG. 6).

The nasal pillows may be as disclosed, for example, U.S. Patent Application Publications 2007/0144525 A1 and 2006/0283461 A1, and International Application PCT/AU2008/001557, filed Oct. 22, 2008, the entire contents of each being incorporated herein by reference. It should also be appreciated that the nasal pillows may be as described in, for example, U.S. Pat. No. 7,318,437, the entire contents of which are incorporated herein by reference. It should further be appreciated that in addition to nasal pillows, the patient interface structure may include nasal pillows or prongs as disclosed, for example, in U.S. Pat. No. 4,782,832 (Trimble), U.S. Pat. No. 7,201,169 (Wilkie et al.), U.S. Pat. No. 7,059,328 (Wood), and WO 2000/074758 (Lovell). It should also be appreciated that the cannula(e) and/or nasal pillows or prongs may include features configured to diffuse the flow of air so that noise may be reduced. Such features are disclosed in, for example U.S. Patent Application Publication 2009/0044808 A1, and WO 2008/014543 A1, the entire contents of each being incorporated herein by reference. Alternative geometries may be possible.

The hollow nozzles 120 are made of a resilient material that may be deformable between a normal position and a compressed position. To assemble the nozzles and the primary headgear, the hollow nozzles are squeezed to resiliently compress them such that the nozzles 120 can be fit into and through the apertures 50, and the nozzles are structured to resiliently expand and return to the normal position once inserted through the apertures and released, so as to interlock the primary headgear with the nozzles.

Thus, the primary headgear, from which the nasal seal is suspended, provides at least one aperture though which at least a portion of the nasal seal is inserted with the primary headgear wrapping about at least one portion of the nasal seal in a sling-like fashion (FIG. 1). The patient interface includes an unobtrusive or low profile nasal seal that may be securely suspended from a relatively small headgear 15. The headgear and nasal seal are structured to inter-engage and/or interlace with one another, without requiring one or more separate clips to connect the headgear to the patient interface, and without requiring a frame or “shell” to which the cushion and clips are sometimes provided.

The nozzles 120 may be provided to or mounted on a common base or gusset portion 130. The nozzles 120 may be formed in one piece with the base or gusset, or they may be attachable and detachable from the base or gusset.

The center section 60 of the headgear 15 is provided or sandwiched between the nozzles 120 and the base or gusset portion.

Each nozzle includes a stalk 140 provided to the base or gusset portion and a generally cone shaped head 150 provided to a distal end of the stalk, the cone shaped head 150 extending through the respective aperture. Each cone shaped head includes a base surface 155 oriented to face the base or gusset portion 130, each base surface 155 being structured to engage the respective rim 65 (FIG. 6) in an assembled and suspended condition. The arms 70 are adjusted relative to the pad 20 to maintain the nasal seal in close proximity contact with the patient's nares, while also maintaining contact between the base surface 155 and rims 65.

Secondary Headgear

It may be desirable to provide fastening arrangements in addition to the primary headgear 15 and/or adhesive or adhesive pad 20 for positioning and stabilizing the patient interface structure in engagement with the patient's face. The use of additional fastening arrangements, or materials, permit the position of the patient interface structure and/or the position of the fastening arrangement to be adjusted to provide a comfortable fit while providing efficient therapy via the flow of breathable gas. The secondary headgear may assist in counteracting tube drag forces and thereby stabilize the seal in position on the patient's face.

For example, while the patient interface system of FIGS. 1-3 may be secured to the patient's face using the primary headgear 15 (optionally in conjunction with the adhesive pad 20), the system may include further structure to better ensure that the nasal seal remain in sealing contact with the patient's airways. For example, the patient interface may include a secondary headgear 175 (FIG. 7). As shown in FIGS. 8-9, the secondary headgear 175 may extend around the back of the patient's head and/or underneath the patient's ears. For example, the secondary headgear 175 is dimensioned and configured to extend below the ears of the patient in use.

The secondary headgear 175 may be connected to or interact with the remainder of the system in a number of different manners.

As best shown in FIG. 7, the secondary headgear 175 includes two adjustable length portions 190 connected by a buckle 195. Each length adjustable portion includes a hook portion 200 and a loop portion 205. One or more adjustable length portions are also possible.

In an alternative shown in FIG. 8, the secondary headgear 175 may be connected to laterally spaced portions of the primary headgear 15, e.g., by placing hooks 180 on the primary headgear.

For example, as shown in FIG. 9, the secondary headgear 175 is connected to lateral side portions or connectors of the nasal seal. Such connectors may be like those described in relation to WO 2009/052560, published Apr. 30, 2009, incorporated herein by reference in its entirety. In an alternative, the secondary headgear may have one end that is integral with or in one piece with the nasal seal, and another end that can be connected and disconnected relative to the nasal seal.

The primary and secondary headgears 15, 175 may be separate, integrally formed and/or connectable with one another, or they may be formed in one piece with one another.

Nares Seal to Encompass Both Nasal Openings/Nares

The nasal seal may be in the form of a nares seal portion to substantially surround both nasal openings of the patient. The nasal seal may include a stub that extends through the at least one aperture of the primary headgear such that a junction region formed between the seal portion and the stub engages the rim.

FIGS. 22-25 show another example of the present technology, which also includes a patient interface system including a nasal seal 10 and a primary headgear 15 that is suspended from the patient's face by an adhesive pad 20 adhered to the nasal bridge region of the patient's face. However, the nasal seal 10 is in the form of a nares seal that seals around both nares in the small region between or in the vicinity of the upper lip and the tip of the user's nose, as described in relation to PCT/AU2010/00684, incorporated herein by reference in its entirety.

Nasal seal includes a face contacting side 220. FIG. 23-25 show the nasal seal and primary headgear in various orientations, to clearly show a nares portion 225 of the seal that engages with the nares and an upper lip portion 230 that engages with the upper lip. Nasal seal also includes an opposite side that includes a stub 240 for connection to an elbow 250 or air delivery tube 255 that delivers gas at pressures of up to 2-40 cm H₂O, e.g., appropriate for treatment of respiratory or sleep related illness.

The primary headgear 15 may include a center section that includes only a single aperture 50 (FIGS. 15 and 22) though which the stub 240 extends. The aperture may be oval or approximately oval and extends in a width-wise direction of the center section. As shown in FIG. 15, a front perimeter portion 100 of the center section 60 may be shaped to match the oval shaped aperture. A rear perimeter portion 110 of the center section 60 is concave adjacent the aperture (to accommodate the septum/upper lip).

While the technology has been described in connection with what are presently considered to be the most practical and preferred examples, it is to be understood that the technology is not to be limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the technology. Furthermore, each individual component of any given assembly, one or more portions of an individual component of any given assembly, and various combinations of components from one or more embodiments may include one or more ornamental design features. In addition, while the technology has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, COPD, morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications. 

What is claimed is:
 1. A patient interface system comprising: a nasal seal of flexible material to communicate with at least one airway of the patient; and a primary headgear to which the nasal seal is removably attached, said primary headgear including a fabric and/or textile material connected to at least a portion of the nasal seal, with the primary headgear removably attachable to an adhesive strip positioned on the patient.
 2. A patient interface system comprising: a nasal seal of flexible material to communicate with at least one airway of the patient; and a primary headgear including a section having at least one aperture through which at least a portion of the nasal seal extends, wherein the nasal seal is positively located against a rim surrounding the aperture.
 3. The patient interface system of claim 1, wherein the primary headgear is flexible.
 4. The patient interface system of claim 2, wherein the primary headgear includes a fabric and/or textile.
 5. The patient interface system of claim 1, wherein the primary headgear includes a laminate.
 6. The patient interface system of claim 5, wherein the laminate includes a soft first inner layer to face the patient and a second outer layer opposite to the first inner layer.
 7. The patient interface system of claim 1, wherein the primary headgear includes a reinforcing layer to add rigidity to the primary headgear.
 8. The patient interface system of claim 2, further comprising a secondary headgear to extend around the back of the patient's head.
 9. The patient interface system of claim 8, wherein the secondary headgear is adapted to extend below the ears of the patient in use.
 10. The patient interface system of claim 8, wherein the secondary headgear is connected to one or more lateral side portions and/or connectors of the nasal seal.
 11. The patient interface system of claim 10, wherein at least one end of the secondary headgear includes a hook to be secured with a corresponding structure on the nare seal.
 12. The patient interface system of claim 8, wherein the secondary headgear is connected to lateral side portions of the primary headgear.
 13. The patient interface system of claim 8, wherein the secondary headgear includes at least one adjustable length portion connected by a buckle.
 14. The patient interface system of claim 8, wherein the primary and secondary headgears are integrally formed with one another, or are formed in one piece with one another.
 15. The patient interface system of claim 1, wherein the nasal seal comprises a nares seal portion to substantially surround both nasal openings of the patient, and a stub that extends through the at least one aperture of the primary headgear, further wherein a junction region formed between the seal portion and the stub engages the rim.
 16. The patient interface system of claim 1, further comprising a pair of apertures provided in the center section, and the nare seal comprises a pair of generally hollow nozzles that extend through respective ones of the pair of apertures.
 17. The patient interface system of claim 16, wherein the nozzles have a cross sectional size that is greater than a cross sectional size of the apertures in at least one dimension.
 18. The patient interface system of claim 16, wherein the nozzles are made of a resilient material that are deformable between a normal position and a compressed position, and to assembly the nozzles and the primary headgear, the nozzles are squeezed to resiliently compress the material, wherein the nozzles fit into and through the apertures, and the nozzles are structured to resiliently expand to the normal position once inserted through the apertures and released, so as to interlock the primary headgear with the nozzles.
 19. The patient interface system of claim 16, wherein the apertures are round.
 20. The patient interface system of claim 16, wherein the apertures are oval and have major axes that converge towards one another in a direction oriented towards a front side of the nasal seal. 